Intramuscular (IM) or intravenous (IV): Impact of Erwinia asparaginase route of administration on asparaginase activity.

10031 Background: Erwinia asparaginase (Erwinia) 25000 IU/m2 IM was approved in 2011 as a component of treatment for patients with acute lymphoblastic leukemia (ALL) with hypersensitivity to E. coli-derived asparaginase. In 2014, FDA approved the IV route of administration for Erwiniabased on the PK and safety findings described herein. Methods: Data from a single arm PK study in children (1 – 17 yrs) with ALL given Erwinia 25000 IU/m2 IV every Monday/Wednesday/Friday (M/W/F) were evaluated. The proportion of patients with 2-day and 3-day nadir serum asparaginase activity (NSAA) levels ≥ 0.1 IU/mL during the first 2 wks of IV Erwinia was compared to that of IM Erwinia. Population PK (PPK)-based simulations were used to determine IV Erwinia doses that would result in the same proportion of patients with 2-day and 3-day NSAA levels as that achieved with 25000 IU/m2 IM. The safety of IV and IM Erwinia administration was also compared. Results: IV dosing resulted in a mean (%CV) t½ of 7.5 h (24%) compared to ...